1. Technical Field of the Invention
The present invention relates to a vehicle lamp having a light source comprising a plurality of LEDs (light emitting diodes) which can be turned on in switchable lamp lighting modes.
2. Prior Art
Conventional vehicle lamps, such as tail and stop lamps, have been constructed so that they can be turned on in two kinds of lamp lighting modes. A specific arrangement for accomplishing the purpose is to use double-filament light sources, whereby to switch lighting modes of tail and stop lamps, the number of filaments to be heated is changed.
There are also known vehicle lamps that use a plurality of LEDs as light sources, wherein the lighting modes of tail and stop lamps are switched by properly changing the number of LEDs to be turned on.
In case where the number of LEDs to be turned on in such a vehicle lamp is changed casually, the number of light sources looks as if the number thereof were increased or decreased and the position of each light source looks as if the position thereof were varied at the time of switching the lamp lighting modes. Consequently, it is feared that drivers of other vehicles are given an incorrect indication.
Accordingly, it is an object of the present invention to provide a vehicle lamp wherein it is possible to switch lamp lighting modes without giving drivers of other vehicles an incorrect indication even when each light source is formed with a plurality of LEDs.
The present invention is intended to achieve the object described above, and in order to accomplish the object above, predetermined groups of lenses are disposed in front of a plurality of LEDs.
A vehicle lamp according to the present invention comprises a light source having a plurality of LEDs that can be turned on in at least two kinds of lamp lighting modes. The light source is provided with a first LED group comprising at least one LED disposed in the substantially central position of the light source, and a second LED group comprising a plurality of LEDs so disposed as to surround the first LED group. The lamp lighting modes include a first lamp lighting mode wherein only the first LED group is turned on and a second lamp lighting mode wherein the second LED group is turned on.
As long as the vehicle lamp is provided with the light source having the plurality of LEDs, the arrangement of other members that form the lighting device is not limited to any specific arrangement.
As long as the first LED group is disposed in the substantially central position of the light source, the arrangement of the plurality of LEDs forming the first LED group is not limited to any specific arrangement. As long as the second LED group is so disposed as to surround the first LED group, the arrangement of the plurality of LEDs forming the second LED group is not limited to any specific arrangement. For example, arrangements of LEDs forming the first LED group or the second LED group can include a point symmetric arrangement with respect to the central position of the light source or an axial symmetric arrangement with respect to a straight line passing the central position of the light source.
In addition, LEDs forming the first LED group and LEDs forming the second LED group may have the same luminescent color or different luminescent colors.
Although the second LED group is arranged to be turned on in the second lamp lighting mode, turning on the second LED group can include a mode wherein only the second LED group is turned on, and a mode wherein the first LED group together with the second LED group is turned on.
With the arrangement shown above, the vehicle lamp is provided with the light source having the plurality of LEDs which can be turned on in at least two kinds of lamp lighting modes. The light source is provided with the first LED group comprising at least one LED disposed in the substantially central position of the light source and the second LED group comprising the plurality of LEDs so disposed as to surround the first LED group. Moreover, the lamp lighting modes include the first lamp lighting mode wherein only the first LED group is turned on and the second lamp lighting mode wherein the second LED group is turned on, so that the following operation is obtainable.
Specifically, since the first LED group includes at least one LED disposed in the substantially central position of the light source and the second LED group includes the plurality of LEDs so disposed as to surround the first LED group, it is possible to make the light source look as if the light source were turned on around its substantially central position in any one of the following cases: (1) only the first LED group is turned on; (2) only the second LED group is turned on; and (3) where the first LED group and the second LED group are simultaneously turned on.
Therefore, the number of light sources is prevented from appearing as if the number thereof were increased or decreased and the position of the light source is also prevented from appearing as if the position thereof were varied at the time of switching the lamp lighting modes, whereby there is little fear of giving drivers of other vehicles an incorrect indication.
In the vehicle lamp having the light source comprising the plurality of LEDs which are turned on in switchable lamp light modes, it is possible to switch the lamp lighting modes without giving drivers of other vehicles an incorrect indication.
Although the light source may be provided only with the first LED group and the second LED group, the light source may also be provided with a third LED group comprising a plurality of LEDs so disposed as to surround the second LED group. In this case, still more lamp lighting modes can be set up.
With the arrangement above, in case where the first LED group and the second LED group are formed with LEDs having the same luminescent color, the brightness can be varied greatly at the time of switching the lamp lighting modes by lighting the first LED group and the second LED group simultaneously. When the stop lamp is turned on while the tail lamp is kept lighted, drivers of other vehicles and so forth can be made to clearly recognize the lighting of the stop lamp by, for example, forming the first LED group and the second LED group with red LEDs, making the first lamp lighting mode the tail lamp lighting mode and making the second lamp lighting mode the stop lamp lighting mode.
With the arrangement above, on the other hand, in case where the first LED group and the second LED group are formed with LEDs having luminescent colors different from each other, only the second LED group is lighted in the second lamp lighting mode. Consequently, one light source is prevented from being simultaneously lighted with two kinds of luminescent colors, whereby it is possible to switch the lamp lighting modes without giving an incorrect indication to drivers of other vehicles.
When a direction indicator is actuated, an amber turn-signal lamp can be turned on by, for example, forming the first LED group with the red LED and forming the second LED group with amber LEDs, and making the first lamp lighting mode the tail lamp lighting mode and making the second lamp lighting mode the turn-signal lamp lighting mode.
With the arrangement above, provision of a diffusion lens having a plurality of diffusion lens elements in front of the light source can make the luminosity of the whole light source look substantially uniform. Thus, the light source looks more like a single light source.
In this case, provision of a condenser lens in front of the diffusion lens allows required luminous intensity distribution performance of the lighting device to be obtained from the combination of the condenser lens and the diffusion lens.
The light source may be a single light source. However, a sufficient quantity of light can be secured by providing a plurality of light sources in position. In the present invention, a predetermined arrangement of light sources is not particularly limited to a specific arrangement, and the arrangement may be a series arrangement, an annular arrangement or any other type of suitable arrangement.
Moreover, it is possible to adopt a vehicle lamp having a plurality of lamp units by defining the aforementioned vehicle lamp as one lamp unit. In this case, the at least two kinds of lamp lighting modes of each lamp unit are combined to set different combinations between the lamp units in order to make the setting of still more lamp lighting modes feasible.